So I have plans to go long travel in the near future and my truck only has 3500 miles on it. (2014 TRD off road dcsb) . I would like to buy some new rims and use the tires that came on the truck for now, BFG AT. My question is ..... if I buy rims that will fit those tires with the intent of putting bigger tires on when the lt is in place and these tires wear out, should I purchase a certain size, offset etc...... Mind the tires now are for 16" wheels ?

Just hold off on the rims until you do everything because 17s will give you more tire options.

I built a new truck and I have few regrets. However, in my mind I still feel like I'm saving money because for me it was between a built Tacoma or a raptor. But be warned whatever route you go Long travel costs money. By the time I add a cage, links, 9", and supercharger, my truck will be sitting at exactly 60k (including purchase price) to have a professionally built truck.

All the nice double cab tacos I see that are not beat to hell are 30k + so I don't know where people are buying crew cab 4x4 long travel trucks for 10k. I know it's very expensive however this is why I bought the truck. If I wanted a nice cruiser I would've bought a full size nice truck.